Someone got it right, the gang is the Purple Gang!
One prominent club in the Detroit area from the 1920s until 1946 was The Chesterfield Club. During this time Capone ran Chicago, but Detroit belonged to The Purple Gang. This gang had such a reputation for violence and brutality that even Capone was careful never to cross them. The Chesterfield Club was one of their joints though it was ostensibly owned and operated by partners George “Dutch” Weinbrenner, Danny Sullivan and Lincoln Fitzgerald.